Light-Assisted Synthesis of Metal Oxide Heirarchical Structures and Their Catalytic Applications

King’ondu, Cecil K.; Iyer, A. N.; Njagi, Eric C.; Opembe, Naftali N.; Genuino, Homer C.; Huang, Hui; Ristau, R. A.; Suib, Steven L.

doi:10.1021/ja109709v

Cited by 71 publications

(46 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…No obvious change emerges yet in the XRD pattern (curve d). This implies that the photoelectrochemical deposited CoOOH is X-ray amorphous, which is in accordance with the work reported by Seabold and Choi [16] and King'ondu et al [17].…”

Section: Characterization Of Pec Behaviors and Photoeletrocatalytic Asupporting

confidence: 92%

Effect of CoOOH loading on the photoelectrocatalytic performance of WO3 nanorod array film

et al. 2013

Applied Surface Science

View full text Add to dashboard Cite

Section: Characterization Of Pec Behaviors and Photoeletrocatalytic Asupporting

confidence: 92%

Effect of CoOOH loading on the photoelectrocatalytic performance of WO3 nanorod array film

et al. 2013

Applied Surface Science

View full text Add to dashboard Cite

“…However, the reported particle sizes were much larger, attesting to the importance of using [Co(NH 3 ) 5 Cl] 2+ salts as precursors to obtain small Co(O)OH nanocrystals. 43 Finally, we also sought to obtain a better understanding of the intermediate(s) involved in the reaction and its overall kinetics. For this, we irradiated a solution of pentaamminechlorocobalt(III) chloride, [Co(NH 3 ) 5 Cl]Cl 2 , starting at pH 6.5.…”

Section: −28mentioning

confidence: 99%

Photochemical versus Thermal Synthesis of Cobalt Oxyhydroxide Nanocrystals

et al. 2012

View full text Add to dashboard Cite

Photochemical methods facilitate the generation, isolation, and study of metastable nanomaterials having unusual size, composition, and morphology. These harder-to-isolate and highly reactive phases, inaccessible using conventional high-temperature pyrolysis, are likely to possess enhanced and unprecedented chemical, electromagnetic, and catalytic properties. We report a fast, low-temperature and scalable photochemical route to synthesize very small (~3 nm) monodisperse cobalt oxyhydroxide (Co(O)OH) nanocrystals. This method uses readily and commercially available pentaamminechlorocobalt(III) chloride, [Co(NH 3 ) 5 Cl]Cl 2 , under acidic or neutral pH and proceeds under either near-UV (350 nm) or Vis (575 nm) illumination. Control experiments showed that the reaction proceeds at competent rates only in the presence of light, does not involve a free radical mechanism, is insensitive to O 2, and proceeds in two steps: (1) Aquation of [Co(NH 3 ) 5 Cl] 2+ to yield [Co(NH 3 ) 5 (H 2 O)] 3+ , followed by (2) slow photoinduced release of NH 3 from the aqua complex. This reaction is slow enough for Co(O)OH to form but fast enough so that nanocrystals are small (ca. 3 nm). The alternative dark thermal reaction proceeds much more slowly and produces much larger (~250 nm) polydisperse Co(O)OH aggregates. UV-Vis absorption measurements and ab initio calculations yield a Co(O)OH band gap of 1.7 eV. Fast thermal annealing of Co(O)OH nanocrystals leads to Co 3 O 4 nanocrystals with overall retention of nanoparticle size and morphology. Thermogravimetric analysis shows that oxyhydroxide to mixed-oxide phase transition occurs at significantly lower temperatures (up to T = 64 degrees C) for small nanocrystals compared with the bulk. KeywordsAb initio calculations, Aqua complexes, Catalytic properties, control experiments, fast thermal annealing, free radical mechanism, high-temperature pyrolysis, low temperatures, monodisperse, nanoparticle sizes, neutral pH, Oxyhydroxides, Pentaamminechlorocobalt, Photochemical method, thermal synthesis, chlorine compounds, cobalt, cracking (chemical) Disciplines Chemistry CommentsReprinted (adapted) with permission from Journal of Physical Chemistry C 116 (2012)

show abstract

“…However, the photocatalytic efficiency of H 2 generation from proton reduction over polymeric carbon nitride is usually low due to (1) limited visible-light absorption; (2) low efficiency in electron-hole separation; (3) lack of surface active sites for H 2 evolution [8,9]. Inspired by the shape-directed functionality in nanoscale, researchers have reported a variety of photocatalysts with specific morphology and microstructure that improve sunlight harvesting and charge-carrier separation [10][11][12]. In particular, the hierarchical microsphere has received great attentions for high photocatalytic activity, and promoted mass and charge transport in the packed-bed flow systems [12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Template-free synthesis of porous graphitic carbon nitride microspheres for enhanced photocatalytic hydrogen generation with high stability

Liao

Yin

et al. 2015

Applied Catalysis B: Environmental

217

106

View full text Add to dashboard Cite

Light-Assisted Synthesis of Metal Oxide Heirarchical Structures and Their Catalytic Applications

Cited by 71 publications

References 32 publications

Effect of CoOOH loading on the photoelectrocatalytic performance of WO3 nanorod array film

Effect of CoOOH loading on the photoelectrocatalytic performance of WO3 nanorod array film

Photochemical versus Thermal Synthesis of Cobalt Oxyhydroxide Nanocrystals

Template-free synthesis of porous graphitic carbon nitride microspheres for enhanced photocatalytic hydrogen generation with high stability

Contact Info

Product

Resources

About